Uptake of tritium-labelled testosterone by rat femur: effect of disuse and age

Male rats 1 or 2 months of age at the beginning of the experiment were used. In each animal one leg was immobilized and the contralateral leg was used as control. Immobilization was maintained for 1, 2, or 3 weeks in each age group. Uptake of 3H-testosterone was measured in both femurs of each animal. Uptake of tritiated hormone decreased with age. Immobilization increased hormone uptake. The effect of immobilization on uptake varied with age. Variation in hormone uptake is proposed as an explanation of previously observed reversal of the effect of testosterone upon osteopenia of disuse in rats in these same age groups.

Subcellular distribution of radioactivity in the prostate gland following the single injection of [1,2-3H] testosterone

Single injections of [1,2-3H] testosterone (100 μCi/kg) to normal mice revealed substantial amounts of radioactivity in the anterior lobes of the prostate gland. Levels of radioactivity were considerably higher in organs obtained from mice injected by the intraperitoneal route than levels in organs obtained from mice that had received subcutaneous injections.

At five minutes following the injection of tritiated testosterone most of the radioactivity was found in the 1000 × g pellet. Lesser amounts were found in the 100 000 × g supernatant.

Castration caused an increase in the amount of radioactivity found in the prostate gland. However this increased uptake was not observed until at least three days following orchidectomy.

Effects of a single injection of testosterone and-or ethinyloestradiol upon mouse prostate gland fructose levels

Single injections of testosterone (20 mg/kg) to castrated mice caused an early stimulation in TCA-extractable fructose. Later, and at somewhat higher doses, free fructose levels were observed to rise. The earliest detectable changes occurred about 12 h following injection.

Single injections of ethinyloestradiol to recently castrated mice (48 h) caused a stimulation of prostate gland TCA-extractable fructose 12 h after hormone administration. Free fructose in these same organs was generally reduced by the administration of this oestrogen.

Ethinyloestradiol given one hour prior to a fructose stimulating dose of testosterone produced essentially the same stimulatory response as ethinyloestradiol alone.

The stimulatory action of ethinyloestradiol is probably related to changes in membrane permeability in the target organ.